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PHP深入观察者模式

程序员文章站 2022-05-25 11:42:11
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####观察者模式* 设计观察者是为了让一个对象跟踪某个状态,知道状态如何改变,一旦状态改变,所有订阅的对象都能得到通知#####使用SPL实现观察者模式* Splsubject 接口有三个抽象方法 attach(),detach(),notify()这些方法不返回任何结果* SplObserver 接口有一个方法update()它会得到subject状态的最新状态并交给观察者实例* SplObjectStorage 类描述为从对象到数据或对象集的一个映射```observers = new SplObjectStorage();    }    //添加观察者    public function attach(\SplObserver $observer){        $this->observers->attach($observer);    }	//删除观察者    public function detach(\SplObserver $observer){        $this->observers->detach($observer);    }    //通知转发    public function notify(){        foreach($this->observers as $observer){            $observer->update($this);        }    }    //设置数据    public function setData($dataNow){        $this->data = $dataNow;    }    public function getData(){        return $this->data;    }}//SPL具体观察者class ConcreteObserver implements SplObserver{    public function update(SplSubject $subject)    {      echo $subject->getData();    }}class Client{    public function __construct()    {        echo "

create three new concrete observers "; //创建观察者 $ob1 = new ConcreteObserver(); $ob2 = new ConcreteObserver(); $ob3 = new ConcreteObserver(); $subject = new ConcreteSubject(); $subject->setObservers(); $subject->setData("here is u data".""); $subject->attach($ob1); $subject->attach($ob2); $subject->attach($ob3); $subject->notify(); echo "

Reset data and reattach ob3

"; $subject->setData("more data that only".""); $subject->attach($ob3); $subject->attach($ob2); $subject->notify(); }}$data = new Client();```#####*的PHP和观察者模式```observers,$obser); } public function detachObser(Observer $obser){ //从数组中移除 数据 $position = 0; foreach($this->observers as $viwer){ ++$position; if($viwer == $obser){ array_splice($this->observers,($position),1); } } } public function notify(){ foreach($this->observers as $viewer){ //调用update方法 $viewer->update($this); } }}class ConcreteSubject extends Subject{ public function setState($stateSet){ $this->stateNow = $stateSet; } public function getState(){ return $this->stateNow; }}class ConcreteObserverDT implements Observer{ private $currentState; public function update(Subject $subject) { $this->currentState = $subject->getState(); echo "DT"; }}class ConcreObserverTablet implements Observer{ private $currentState; public function update(Subject $subject) { $this->currentState = $subject->getState(); echo "tablet"; }}class ConcreObserverPhone implements Observer{ private $currentState; public function update(Subject $subject) { $this->currentState = $subject->getState(); echo "phone"; }}class Client{ public function __construct() { $sub = new ConcreteSubject(); $ob1 = new ConcreObserverPhone(); $ob2 = new ConcreObserverTablet(); $ob3 = new ConcreteObserverDT(); $sub->attachObser($ob1); $sub->attachObser($ob2); $sub->attachObser($ob3); $sub->setState("fuck"); $sub->detachObser($ob1); $sub->notify(); }}$data = new Client();```